Hi Marion, Don't know how is it from QGIS, but in the native GRASS GIS we first se the computational region with g.region [0] and then run r.mapcalc as:
r.mapcalc expression="diff = map1 - map2" HTH, Vero [0] https://grass.osgeo.org/grass74/manuals/g.region.html El lun., 2 jul. 2018 a las 12:18, marion-brunet (<[email protected]>) escribió: > Hello, > > I am trying to calculate the difference between two raster layers. For > that, I am using GRASS in QGIS. I use the command r.mapcalc. In the field > "expression to evaluate" I wrote > r.mapcalc expression=diff =TIN_12_17-TIN_06_18 > TIN_12_17 and TIN_06_18 are the names of my two rasters. > I then select the region on my canevas. > When I click "run" I don't have any error but no file is created in my > project. I would like to have a new raster file with the difference of the > two previous ones. > > What am I doing wrong? > > Thank you, > Marion_______________________________________________ > grass-user mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/grass-user
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